1. Field of the Invention
The present invention relates generally to a lens cover apparatus for a camera, and more particularly to a lens cover and a driving device for the lens cover, which is provided between the body and a casing of the camera and uncovers and covers a lens in a lens barrel by opening and closing an opening of the casing, which faces a fixed cylinder of the lens barrel.
2. Description of Related Art
U.S. Pat. No. 4,283,132 discloses a lens cover for protecting a lens of a camera while the camera is unused. The lens cover is provided between the body and a casing of the camera so that the lens cover can pivot to open and close an opening of the casing that faces the lens. The lens cover protects the lens by closing the opening.
The lens cover is driven by a mechanism with a drive ring. The drive ring is rotatably mounted on the circumference of a fixed cylinder for a taking lens barrel, which is formed on the body of the camera. A power gear engages with teeth formed on the outer peripheral surface of the drive ring. A power transmission member is provided between the drive ring and the lens cover so as to transmit a rotational force of the drive ring to the lens cover. Driving the power gear and rotating the drive ring transmit the rotational force to the lens cover through the power transmission member and turn the lens cover to open and close the opening of the casing.
The conventional lens cover apparatus, however, is designed without taking account of the position of a pivot of the lens cover. More specifically, the conventional camera with the lens cover is large since it is necessary to have a space where the lens cover is recessed while the opening is opened. Moreover, a member for preventing the drive ring from coming off the fixed cylinder is fixed to the end of the fixed cylinder after the drive ring is mounted on the fixed cylinder. This increases the thickness of the camera.
Japanese Patent Provisional Publication No. 2-251829 discloses a camera lens cover apparatus, which has a power transmission mechanism including first and second spring members. The power transmission mechanism transmits a driving force of a lens cover driving motor to the lens cover through the first spring member. If an external force acts on the lens cover, the power transmission mechanism cushions the external force by expanding and contracting the first and second spring members to thereby prevent the damage against the driving mechanism for the lens cover. The conventional lens cover apparatus is designed without considering a position where the power transmission mechanism is arranged in the camera. In short, the camera with the conventional lens cover is large since it is necessary to provide a space for arranging the power transmission mechanism.
A driving mechanism for the lens cover is composed of a lens cover drive motor and a power transmission member for transmitting power of the motor to the lens cover. When the lens cover drive motor is run, its power is transmitted to the lens cover through the power transmission member to drive the lens cover in order to open and close the opening. There is a camera, which has the lens cover and the zoom lens and moves movable lenses of a zoom finder forward and backward so that an image of a subject magnified by a photographic magnification can be seen through the finder.
The movable lenses, which are supported by movable lens holding frames, are arranged in a finder frame in such a manner as to freely move forward and backward. Cam followers project from the movable lens holding frames, and the cam followers are fitted in cam grooves formed on a finder cam. The finder cam connects to a cam drive motor. When the cam drive motor drives the finder cam, the cam followers move along the cam grooves and the movable lens holding frames move forward and backward along the optical axis. Consequently, an image of a subject magnified by a photographic magnification can be seen through the finder. In the conventional camera, however, it is necessary to separately provide the driving mechanism for the lens cover and the driving mechanism for the movable lens holding frames of the zoom finder. Thus, many parts are required for the camera, and the camera is large and heavy.